Preparation and Properties of 2-Hydroxypropyl Methacrylate-Alkyl Acrylate Copolymer Net-Works

Abstract

Hydrogels, in the swollen state, exhibit poor mechanical properties which need to be improved to increase their utility. Polymeric materials with a wide range of physical properties suitable for a broad variety of applications can be prepared using hydrophobic monomers with a variety of crosslinkers. The polymerization of 2-hydroxyethyl methacrylate(HEMA) with ethylene glycol dimethacrylate(EGDMA) in the presence of organic peroxides gave a hydrophilic copolymer useful for coatings, mouldings and carriers for biologically active substances (1). The swelling properties of polyhydroxyalkyl acrylates in water depends to a certain extent on the degree of crosslinking, concentration of additives in the water and the amount of water used in the polymerization process. When HEMA was polymerized in aqueous solution with high water content polymer precipitates out from the monomer and yields opaque gels or porous sponges (2). Mechanical behavior of poly(HEMA) hydrogels prepared in the presence of various concentrations of crosslinking agents and diluents has been investigated. A copolymer prepared from a hydroxyalkyl (meth)acrylate, a crosslinking agent such as EGDMA and an unsaturated acid like methacrylic acid are suitable for manufacturing contact lenses (3).